Paint and process of applying the same



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This invention relates to the coatin or painting of a transparent substance, suc as glass, and particularly to the coating of an incandescentlam bulb.

An object of t e invention is the provision of a method for coating glass and other transparent objects with a paint which is resistant to heat, water, constituents of the atmosphere, etc.

Another object-of the invention is the providingot a process for applying a pigment to transparent objects in such manner that the original color of the pigment is not changed during the process, which occurs in some processes where a chemical reaction is made to take place in the paint.

A further object of the invention is the. provision of a process for imparting to lass or like substance, a coating of uni orm thickness, free from spots and unattended by subsequent scaling.

A still further ob'ect of the invention is the provision of a inding material for a paint which renders the same resistant to eat, water or its vapor, etc.

Other ob'ects of the invention will mani fest themse ves upon a reading of the following description.

The resent processes for coating glass, whiohis to be exposed to outside weather conditions or considerable heat, are defective in that the coatin either peels, changes color, velatilizes or b isters. Some of the present processes give a coating of varying}- thickness which is a defect if the glass or other transparent substance isito be used to transmit light.

In practicing the invention, a solution of sodium silicate is mixed with another com- Application Med December is, n20. sum in. 431,587.

SB LAIMIP COMPANY, A TOOBPOBLTION OF render the sodium silicate resistant to water and certain constituents of the atmosphere. v Sod um silicate is a substance well known as a binding agent for powdered materials.

To render it sufficiently adhesive, it is made as having a ratio of acid to base, i. e., of silica (SiO) to sodium oxide (N 11 0), greater than unity, but with a sufiicient proportion of base or alkali to render it sufiiciently soluble. The solubility which is nec essary in brder to mix nent with the 'sodium silicate and applg ilikmit is a disadvantage if the painted object is to be exposed to water or water-vapor. To make the sodium silicate resistant to the solventaction of water, it is necessary to reduce its alkali content. The present invention does this by adding to the sodium silicate a sufiicient amount of a chemical compound which will react with the sodium silicate to reduce the alkali content of the latter substance until it reaches a composition of minimum aqueous solubility.

'It is also necessary to reduce the proportion of alkali in the sodium silicate on account of the fact that the'iillfilli will absorb from the air such substances as moisture, carbon dioxide and sulphur dioxide, forming soluble salts such as sodium carbonate and other soluble sodium salts. The soluble salts tend to accumulate as a residue on the painted surface and present an objectionroom temperature to reduce the alkali cou Qdntpf the sodium silicate. The substances a dedto the sodium silicate may be fg example, vammonium ,oxalate,' ammonium sill hate, sodium ammonium phosphate. or oxa '0 acid. For the purpose of describing the process, oxalic acid may be assumed as the substance added to the sodium silicate. To the mixture of sodium silicate and oxalic acid the pigmentof the desired color is added in the form'of an impalpabl e powder which is thoroughly distributed throughout the aqueous solution.

means of an air brush, toany esired thickness. By varying e thickness of the coating the color may be varied to different hues. The glas is then exposed to atemperatureof from 125 to 200 in an oven for a period of about three minutes. At this temperature, the oxalic acid combines with put of the alkali of the sodium silicate;

A typical formula which has been successfully used to produce the frosted efi'ect on lamp bulbs is the following: 500 cc. sodium si ion of 1.4 specific gravity, 400

cc. saturated ammonium oxalate solution,

17 grams kaolin.

The solution obtained by using this formula may be sprayed by an air brush a on v an ex osed surface of a lamp-bulb. he lamp is then placed in an oven in which the temperature is in the neighborhood of 175 C., and baked for a period of about three minutes. This gives a hard uniform coating to the lamp bulb treated according to the process 'ust described.

Modi cations of the invention will manifest themselves to those skilled in the art but it is our intention to include such of these as come within thescope of the appended claims.

.The term elevated temperature, as used in the appended claims, is intended to specify a temperature somewhathigher than that of room temperature, i. e., witlnnthereu e of 125 C. to 200 C. 4

ivhat, we claim is: 1. A binding material for a light difl'us;

'ing coating consisting essentially of a solu- ;tion of a mixture of commercial sodium silirate and a substance capable of reducing the alkali content of said sodium silicate when said mixture is heated to render saidcoating resistant to atmospheric conditions.

2. A binding material for a light transmitting coating which consists essentially-0f a solution of sodium silicate and a solution of a compound capable of reacting with the sodium silicate at an elevated temperatureconditions. 3. A binding material for a light trans- F mitti ig coating consisting essentially of a solution of a mixture-of commercial sodium silicate and a substance capable of reducing f hate when said mixture is heated. 9 4. A binding material for a pamtcompris:

.;. The print is the a plied by an suitable means u rave on, by

.ject which consists in to render the coating resistant to atmospheric r 'h ngfthe glass to an elevated tem- 'cember,1920. fthe free alkali content of said sodium siIiinga water solution of amixture of sodium silicate and an organic compound capable of reducing the alkali. content of said sodium silicate when said mixture is heated.

v5. A binding material for a paint ada ted to be applied to transparent objects w ich consists of a water solution of sodium silicate .and ammonium oxalate.

6. A light difi'using paint :consisti-n essentially of a pigment, a solution of sodium silicate and a com ound capable of reacting with the sodium silicate at an elevated temperature to render said paint lesssoluble.

7.-A paint consisting of a igment and a water solution of sodium si mate and ammonium oxalate. v

' 8. The process of coatin a vitreous ob- (1:51p yin thereto. a pi ment, a solution of s um s1 icate and a soiiition of a substance capable of chemically reacting with the sodium silicate and heating the coated object, whereby the paint is rendered resistant to the-action of heat, water and impurities of the atmosphere.

-9. The process of applying a translucent coating of paint to an incandescent. electric lamp which consists in applying, as a paint, a pigment, a solution of sodium silicate and a solution of a substance capable of chemically reacting with the silicate when roduce the alkali content of the sodium silicate after the aint has been applied;

11. The met od of rendering resistant to thesolvent action of -water a aint which compr ses m ning a pigment wit a solution of sodium silicate and a,compound capable -of chemically reacting with sodium silicate when heated, and heating said paint whereby a part of thealkdli is removed from the sodium silicate by the chemical reaction initiated by the heating' v I "12. The of frosting clear glass 'which consists in applying, as a'paint, a

white pigment'held in suspension by a solution of sodium silicate, mixing this solution with a solution of a substance capable of chemicall reacting with the sodium silicate pe'rature.

subscribed our names this 17th day of De- AARONM. 'HAGEMAN. Enwani) R. SCHMID. I 

